quant_energy_mono()

wouldn't hurt

converted to float though)

weighting that didn't seem to help anyway.

intruduces a bit of an encoder-decoder mismatch (Q8 in dB), but it'll be
reduced when the interals of quant_energy_mono() are properly converted to
fixed-point and oldEBands gets rounded instead of truncated.

is used by both by the encoding and decoding functions.